The present invention relates to a readily producible pressure resistant sealed vessel, for example, a sealed vessel used as a liquid tank integrated into a cooling medium circular system of an air-conditioning equipment of an automobile or the like, and a process for producing the same.
Conventionally, a sealed vessel such as a gas bomb, a drinking can or the like has been produced by manufacturing a body portion and a cover portion thereof separately and connecting or coupling the cover to the body portion by means of welding or mechanical fitting, or integrally fabricating both the body portion and the cover. For example, a liquid tank integrated into an air-conditioning equipment of an automobile or the like has functions of controlling an amount of cooling medium circulating in a cooling circular system and filtering the cooling medium by removing moisture or other contaminants such as dusts and wastes and supplying the cleaned cooling medium to a expansion valve, and usually stores high-pressure cooling medium therein. For these reasons, a sealed vessel made of steel which is produced by welding a cover 4 having an inlet pipe 4a and an outlet pipe 4b for the cooling medium to an opening portion of a bottomed cylindrical body portion 1 or an opening portion of a cylindrical body portion 2, another opening portion of which is welded to a cover 3 to form a bottom portion thereof as shown in FIGS. 1 and 2, have been conventionally used. However, it requires much labor to produce the sealed vessels by means of welding as mentioned above, and particularly in the case of using aluminum or aluminum alloy as a material for lightening the sealed vessel completed, the welding procedure itself accompanies difficulties as well as high expenses.
Thus, so as to simplify the process for producing a sealed vessel and reduce its costs for production, a liquid tank is developed which is provided with irregular portions 5 and 5 both on an inner peripheral surface of an opening end of a bottomed cylindrical body portion 1 and on an outer peripheral surface of a cover 4, the cover 4 having an inlet pipe 4a and an outlet pipe 4b for cooling medium so that the recess portions of the outer peripheral surface of the cover 4 engages the convex portions of the inner peripheral surface of the body portion 1 and the convex portion of the inner peripheral surface of the body portion 1 engages the recess portion of the outer peripheral surface of the cover 4 and annular recess grooves 6 and 6 both on the midway of the irregular portions 5, the recess grooves 6 being opposed to each other with maintaining the engagement of the irregular portions 5 and intervening an 0-ring between the annular recess grooves 6 and 6, and the cover 4 being air-tightly fixed to the body portion 1 by uniformly pressing the irregular portion 5 of the bottomed cylindrical body portion 1 to the irregular portion 5 of the cover 4 by means of roller or the like to pressure-weld the inner peripheral surface of the opening end of the body portion 1 to the outer peripheral surface of the cover 4 as shown in FIGS. 3 and 4 (Japanese Utility Model Laid Open No. 62-52858). In the tank, desiccating agent 8, glass wool 9 and mesh 10 are laminated and they are pressed by a press device 11. The cooling medium introduced from an inlet pipe 4b is brought into contact with the desiccating agent 8 and subsequently drawn out through the outlet pipe 4a, whereby moisture and contaminants such as dusts and wastes contained in the cooling medium are removed. In the drawings, reference numeral 12 designates a side glass for observing the inside of the tank and reference numeral 13 designates an 0-ring. Since the liquid tank above-described is fabricated not by welding procedure but by pressure welding its body portion and its cover, it is possible to widely use various materials such as steel, aluminum, aluminum alloy or the like. However, irregular portions 5 must be provided on the inner peripheral surface of the open end of the body portion 1 having a relatively thin thickness and the outer peripheral surface of the cover 4 so that the recess portion of the irregular portion 5 of the body portion 1 engages the convex portion of the cover 4 and the convex portion of the irregular portion 5 of the body portion 1 engages the recess portion of the cover, respectively and the annular grooves 6 and 6. In addition, the relative positioning or embedding relationship of the respective recess and convex portions of the inner peripheral surface of the open end of the body portion 1 with the respective convex and recess portions of the cover 4 must be maintained without any deviation therebetween upon fixing the cover 4 to the body portion 1.